In related art, a brake mechanism is known which combines the M/C pressure generated by depressing a brake pedal and the brake pressure applied by brake fluid pressure increasing means for sucking out brake fluid from the M/C and pressurizing the brake fluid, and which supplies the combined pressures to the W/C, thereby performing pressurization such that the W/C pressure is higher than the M/C pressure (refer to Patent Literature 1, for example). This brake mechanism performs control such that, during an ineffective stroke from the beginning of the depression of the brake pedal to the closure of a port of a master reservoir provided in the M/C, the amount of pressurization is increased in accordance with a stroke amount, and after the port is closed, the W/C pressure is increased in accordance with an increase in the M/C pressure and the braking force is increased while the amount of pressurization is maintained.